[PATCH 6.6 043/301] riscv, bpf: Fix incorrect runtime stats

Greg Kroah-Hartman
2024-05-14T11:00:47Z

From: Xu Kuohai <xukuohai@huawei.com>

[ Upstream commit 10541b374aa05c8118cc6a529a615882e53f261b ]

When __bpf_prog_enter() returns zero, the s1 register is not set to zero,
resulting in incorrect runtime stats. Fix it by setting s1 immediately upon
the return of __bpf_prog_enter().

Fixes: 49b5e77ae3e2 ("riscv, bpf: Add bpf trampoline support for RV64")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240416064208.2919073-3-xukuohai@huaweicloud.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/riscv/net/bpf_jit_comp64.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 8581693e62d39..b3990874e4818 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -740,6 +740,9 @@ static int invoke_bpf_prog(struct bpf_tramp_link *l, int args_off, int retval_of
if (ret)
return ret;

+ /* store prog start time */
+ emit_mv(RV_REG_S1, RV_REG_A0, ctx);
+
/* if (__bpf_prog_enter(prog) == 0)
* goto skip_exec_of_prog;
*/
@@ -747,9 +750,6 @@ static int invoke_bpf_prog(struct bpf_tramp_link *l, int args_off, int retval_of
/* nop reserved for conditional jump */
emit(rv_nop(), ctx);

- /* store prog start time */
- emit_mv(RV_REG_S1, RV_REG_A0, ctx);
-
/* arg1: &args_off */
emit_addi(RV_REG_A0, RV_REG_FP, -args_off, ctx);
if (!p->jited)
--
2.43.0